Structure of nanoscale polaron correlations in La 1.2 Sr 1.8 Mn 2 O 7

A system of strongly interacting electron-lattice polarons can exhibit charge and orbital order at sufficiently high polaron concentrations. In this study, the structure of short-range polaron correlations in the layered colossal magnetoresistive perovskite manganite ${\mathrm{La}}_{1.2}{\mathrm{Sr}}_{1.8}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ has been determined by a crystallographic analysis of broad satellite maxima observed in diffuse x-ray and neutron-scattering data. The resulting $\mathbf{q}\ensuremath{\approx}(0.3,0,\ifmmode\pm\else\textpm\fi{}1)$ modulation is a longitudinal octahedral-stretch mode, consistent with incommensurate Jahn-Teller-coupled charge-density-wave fluctuations, that implies an unusual orbital-stripe pattern parallel to the $〈100〉$ directions.